Three girls, Gillian, Kathy and Sabrina had a total of 960 coins. Some exchanges were made. First, Gillian gave Kathy as many coins as Kathy had. After that, Kathy gave
15 of whatever she had then to Sabrina. Finally, Sabrina gave
15 of whatever she had to Gillian. As a result, they each had the same number of coins. How many coins did Gillian have at first?
|
Gillian |
Kathy |
Sabrina |
Total |
Before 1 |
? |
1 u |
|
960 |
Change 1 |
- 1 u |
+ 1 u |
|
|
After 1 |
|
2 u |
|
|
Before 2 |
|
5 p |
|
960 |
Change 2 |
|
- 1 p |
+ 1 p |
|
After 2 |
|
4 p |
|
|
Before 3 |
|
|
5 boxes |
960 |
Change 3 |
+ 1 box |
|
- 1 box |
|
After 3 |
|
|
4 boxes |
|
After 3 |
1 group |
1 group |
1 group |
960 |
3 groups = 960
1 group = 960 ÷ 3 = 320
1 group = 4 boxes 4 boxes = 320
1 box = 320 ÷ 4 = 80
4 p = 1 group
1 p = 320 ÷ 4 = 80
5 p = 5 x 80 = 400
5 p = 2 u
2 u = 400
1 u = 400 ÷ 2 = 200
Number of coins that Gillian had at first
= 1 group - 1 box + 1 u
= 320 - 80 + 200
= 440
Answer(s): 440